A pet carrier can be a relatively small hand held fishing tackle like box for a cat. A pet carrier can be a relatively large crate like holder for a dog.
Access to the inside of the pet carrier may be via a wire gate on the front, side or top of the carrier. If the pet carrier is designed for a dog, the wire gate may be removable such that the dog can come and go as he or she pleases.
Pet carriers can be designed simply as a cage, with all six sides of the carrier being wire or wire like, where the six sides are the front, rear, right side, left side, top, and bottom of the parallelepiped pet carrier. Large carriers, such as those designed for dogs, may be formed of plastic and include opaque walls with relatively few windows so as to provide a secure cave like home for a dog.
Pet carriers may be designed for use in vehicles, such as for placement in the rear of a sport utility vehicle or in the rear of a station wagon. A pet carrier may double as a temporary or portable dog house.